Field of the Invention
The invention relates to a method for producing semiconductor chips from a wafer. The invention is particularly directed to the method step of separating the individual semiconductor chips from one another and to separate them out of the wafer.
It has thus far been conventional to separate semiconductor chips from one another and the wafer by sawing the chips out of the wafer, or by scoring the wafer surface and breaking the chips out of the wafer. Despite efforts toward improving sawblades and the sawing apparatus, the sawblades used in the sawing as a rule have a thickness of more than 30 .mu.m. The attendant loss of semiconductor material is correspondingly high, and the spacing between the individual semiconductor chips must be relatively great. This in turn means that only relatively few semiconductor chips can be accommodated on one wafer.
Moreover, in the sawing of the semiconductor chips, damage in the form of microscopic cracks or flaking occurs, which must be minimized in a separate etching step, so-called damage etching.
Similar disadvantages arise in scoring and breaking semiconductor chips as well. For instance, in sawing semiconductor chips with an edge length of 200 .mu.m, material losses of approximately 36% are observed. This proportion rises with decreasing chip size, and for chips with an edge length of 150 .mu.m it amounts to approximately 44%. The conventional methods are accordingly unsatisfactory from a commercial, economic standpoint.